Sleep apnea is a medical condition that affects the sleep of many people. Physicians use a device called a continuous positive airway pressure (CPAP) machine to treat sleep apnea. A CPAP machine requires a patient to wear a mask over the face while sleeping. Some CPAP masks cover only the patient's nose, while others cover both the patient's mouth and nose. Straps that attach the mask to the patient's head create marks on the head and face, and can even cause changes in tissue, leaving patients with puffy eyes, enlarged nasal openings, or indentations in the forehead.